Secondary recovery of earth fluids



April 28, 964 T. PENNINGTON u 3,130,784

SECONDARY RECOVERY OF EARTH mums Filed Dec. 1, 1961 2 Sheets-Sheet l FIG. I. FIG.2. FIG.4.

POSITIONING CASING DUMMY mvmog THOMAS PENNINGTON,]I,

ATTORNEY.

April 28, 1964 T. PENNINGTON 11 3,130,784

SECONDARY RECOVERY OF EARTH FLUIDS Filed Dec. 1, 1961 2 sheets sheet 2 l" Av 20 FIG. 5' A 1 4 l lll I FIRING DEVICE F'RING/ a 22 PIN 32 i l I I SOUIB/ i 36 g I. I9 PRmAcoRo FIG. 7.

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-3O LU 6/ SLOT I2 4J1 THOMAS PENNINGTONJI.

United States Patent 3,130,784 SECONDARY RECOVERY OF EARTH FLUIDS Thomas Pennington H, Houston, Tex., assignor, by mesne assignments, to Jersey Production Research Company, Tulsa, Okla., a corporation of Delaware Filed Dec. 1, 1961, Ser. No. 156,218 3 Claims. (Cl. 166-42) This invention relates generally to secondary recovery of hydrocarbonaceous earth fluids, and more particularly to the injection of fluids int-o selected productive earth formations under conditions wherein a borehole penetrates a plurality of productive earth formations.

Secondary recovery of formation fluids usually involves the injection of liquid or gaseous fluids into a so-called injection well to stimulate flow of formation fluids to well bores through which the earth fluids are transmitted to the earths surface. In many locations it is desirable to eithersimultaneously or consecutively inject fluids into a plurality of vertically spaced productive earth formations through a single injection Well. The usual manner of accomplishing this purpose has been to perforate casing opposite the formations into which fluids are to be injected, and to suspend within the casing a plurality of tubing strings, one for each of the formations to be injected. Fluid is then introduced into each tubing string and injected into the various productive earth formations. Such a technique is quite expensive in view of the cost of the casing and the plurality of pipe strings. Manifestly, it is desirable to minimize the number of. pipe strings through which fluids are injected into the plurality of earth formations.

In accordance with one aspect of the present invention, a plurality of side pocket mandrels in a continuous-bore pipe string are positioned in a borehole at the level of each earth formation into which fluids are desired to be injected. The pipe string is cemented to the walls of the borehole from the bottom of the borehole to a level above the uppermost productive earth formation. The side pockets are thereupon perforated in a direction away from the bore of the pipe string. The side pockets opposite earth formations through which it is desired not to inject fluids are blanked off and fluids are injected into the other productive earth formations through check valves inserted in the side pockets opposite said other earth formations.

Objects and features of the invention not apparent from the above discussion will become evident upon consideration of the following description thereof when taken in connection with the accompanying drawings, wherein:

FIGS. 1 through 4 are schematic diagrams of a well installation illustrating various steps involved in the method aspect of the invention;

FIG. 5 is an elevational view, partially in cross section, of a portion of a side pocket mandrel as illustrated in FIG. 3 having positioned therein an oriented perforating gun for perforating .the side pocket away from the bore of the mandrel; FIG. 6 is a cross-sectional view taken along section 66 of FIG. 5;

FIG. 7 is an elevational view, partially in cross-section, of a firing device such as used in the perforating gun illustrated in FIG. 5; and

FIG. 8 is a view of the portion of the side pocket mandrel illustrated in FIG. 5 having positioned in the side pocket a check valve in the manner illustrated in FIG. 4.

The term side pocket mandrel, as used herein, is a term of art in common use in oil field practice referring to a pipe string section to be connected as an integral part of a Well pipe string, having a conduit portion and a side pocket positioned side-by-side therein. The side 7 3,130,784 Patented Apr. 28, 1964 pocket of the mandrel is out of alignment with the bore of the pipe string and mandrel, and various types of well tools, such as gas lift valves, may be inserted thereinto. Such side pocket mandrels are illustrated at pages 1084 and 1085 of the Composite Catalog of Oil Field Equipment and Services, 23rd Revision (World Oil, 1958), along with mandrels having a pocket located in line with the bore of a tubing string, and should be distinguished therefrom.

In each of FIGS. 1 through 4 there is illustrated a borehole 2 penetrating a plurality of productive earth formations designated A, B, and C. Positioned in the borehole are a plurality of substantially identical side pocket mandrels 3, 7, and 11 interconnected by pipe string sections and suspended in the borehole from an uppermost pipe string section extending to the earths surface so as to provide a. single pipe string extending from the earths surface to substantially the bottom of the borehole. A cementing shoe 15 is connected to the bottom end of the pipe string section depending from the lowermost mandrel. In FIGS. 2, 3, and 4 the pipe string is shown as being suspended from a Wellhead which may be of conventional design and which includes a valved line 18 having a control valve 23 therein.

Before proceeding further with a discussion of FIGS.

1 through 4, it is well to describe the apparatus illustrated in FIGS. 5 through 8. In FIG. 5 there is shown a portion of a mandrel, for example mandrel 7. The mandrel includes a side pocket 16 having ports 26A and 26B at the lower end thereof for fluid communication between the bore 14 of the mandrel and the interior of the side pocket 16. At the lower end of the side pocket 16 there is provided an orienting slot 12 (see FIG. 6) and a pair of oppositely and downwardly spiraling guide shoulders 34A and 3413 for guiding a lug into the slot 12. Shown positioned in the side pocket is a perforating gun 19 including a pair of perforating means 24 in the body portion thereof. The perforating means is here shown as being of the type utilizing shaped charges, although other types of perforators, such as those using bullets, may be used. At the upper end of the perforating gun 19 is a fishing neck 29, to which a suitable placement tool, such as a Cameo type R kickover tool, can be latched. Immediately below the fishing neck 20 is a firing apparatus 22 which may be of the type described below with respect to FIG. 7, or a clock-actuated type such as has been used in perforating guns. At the bottom end 'of the perforating gun 19 is a tubular extension member 39 having an orienting lug 28 extending therefrom adapted to engage either of shoulders 34A or 34B and to slide into slot 12. When the lug 28 is in slot 12, the direction of perforation of gun 19 is away from the bore 14 of the mandrel. The firing mechanism illustrated in FIG. 7 includes a squib 36 adapted to detonate upon being struck by firing pin 32. The squib 36 is connected to the shaped charges 24 by an explosive line 36A, which may be of the type usually designated primacord. The firing pin 32 is held suspended in cavity 22A by a shear pin 34. Coil spring 32A engages the upper end of the firing pin 32 to drive the firing pin downwardly when shear pin 34 is sheared. The upper end of the cavity 22A is ported by ports 40 so as to be in hydraulic communication with the pipe string bore through the upper end of the side pocket. Exertion of hydraulic pressure on the upper end of the firing pin shears shear pin 34 to permit the firing pin to be driven against squib 36 by spring 32A and the downward force of the hydraulic pressure.

In FIG. 8 a check valve housing 21 is shown positioned in the side pocket 16. The check valve housing has connected at the upper end thereof a fishing head 25. Annular sealing members 29 and 35 seal the perforations 33 in the side pocket from fluid communication with the bore of the mandrel except through the valve. The body 27 of the check valve includes a central upper bore 21A which is ported betweenthe sealing elements 29 and 35 to provide fluid communication from the bore 21A to the perforations 33. The check valve includes a ball 41, a spring 39, and a spider ring 37. Fluid entering the lower end of the check valve through ports 45 will unseat the ball 41 when the pressure of spring 39 has been overcome so that fluid flows through ring 37 and out ports 31 and perforations 33 into the earth formation surrounding the mandrel.

With reference again to FIGS. 1 through 4, in FIG. 1 the pipe string is shown being positioned in the borehole so that the mandrels 3, 7, and 11 are opposite the earth formations A, B, and C, respectively, into which the fluids are to be injected. The perforations in the side pocket are blanked off by dummy tools 5, 9, and 13. Cement is circulated down the pipe string, as shown in FIG. 2, and up the annulus therearound to a level above the uppermost earth formation A. The purpose of inserting the dummies 5, 9, and 13 in the side pockets during the cementing operation is to prevent cement from entering the side pockets inasmuch as cement would be virtually impossible to remove. After the cement has set, if it is desired to inject fluids into formation B, dummy 9 may be removed and a perforating gun run into the well on a suitable device such as a Camco type R kickover tool. When the gun has been inserted in side pocket 7, the kickover tool is removed from the Well and fluid pressure in the well is increased to actuate the gun. The other mandrels 3 and 11 may be perforated in the same manner. When it is desired to inject fluid into a given earth formation, such as formation B, dummies are again inserted in the side pockets opposite the earth formations into which it is not desired to inject fluids, such as side pockets 3 and 11, so as to isolate the perforations from the pipe string bore. A check valve, such as that illustrated in FIG. 8, is inserted in side pocket 7. Fluids thereupon are pumped through the pipe string and the check valve 21 into the earth forma tion B.

Manifestly, it is feasible to simultaneously inject fluids into more than one earth formation inasmuch as the check valves will pass fluids at a known rate at a given pressure. It is therefore practicable to inject fluids at known flow rates to as many earth formations as desired.

The invention is not necessary to be restricted to the specific structural details or arrangement of parts herein set forth, as various modifications thereof may be effected without departing from the spirit and scope of the invention.

The objects and features of the invention having been completely described, what I wish to claim is:

1. A method of injecting fluids into a plurality of hydrocarbon-productive earth formations penetrated by a borehole, comprising:

positioning a side pocket mandrel adjacent each of said earth formations interconnected and suspended from the earths surface by pipe string sections to form a single pipe string having a continuous bore extending from the earths surface to substantially the bottom of the borehole;

cementing the pipe string to the walls of the borehole from the borehole bottom to a level above the uppermost of said hydrocarbonproductive earth formations; 5 successively positioning a perforating gun in the side pockets of said mandrels and perforating said mandrels through the side pockets; blanking off all but one of said perforated side pockets;

and inserting check valve means in at least one side pocket, and injecting fluids through said check valve means and the perforations in said at least one side pocket. 2. A method of injecting fluids into a plurality of hydrocarbon-productive earth formations penetrated by a borehole, comprising:

positioning a side pocket mandrel adjacent each of said earth formations interconnected and suspended from the earths surface by pipe string sections to form a single pipe string having a continuous bore extending from the earths surface to substantially the bottom of the borehole; cementing the pipe string to the walls of the borehole from the borehole bottom to a level above the uppermost of said hydrocarbon-productive earth formations; successively orienting a perforating gun in the side pockets of said mandrels so that the direction of perforation thereof is away from the bore of the pipe string, and actuating the perforating gun after each orientation thereof; blanking off all but one of said perforated side pockets;

and inserting check valve means in at least one side pocket, and injecting fluids through said check valve means and the perforations in said at least one side pocket. 3. A method of injecting fluids into a plurality of hydrocarbon-productive earth formations penetrated by a borehole, comprising:

positioning a side pocket mandrel adjacent each of said earth formations interconnected and suspended from the earths surface by pipe string sections to form a single pipe string having a continuous bore extending from the earths surface to substantially the bottom of the borehole; cementing the pipe string to the walls of the borehole from the borehole bottom to a level above the uppermost of said hydrocarbon-productive earth formations; successively orienting a perforating gun in the side pockets of said mandrels so that the direction of perforation thereof is away from the bore of the pipe string, and actuating the perforating gun after each orientation thereof; blanking off all but one of said perforated side pockets;

and injecting fluid into the formation through the perforations in said one side pocket.

Corley Dec. 6, 1960 Payne Feb. 28, 1961 

1. A METHOD OF INJECTING FLUIDS INTO A PLURALITY OF HYDROCARBON-PRODUCTIVE EARTH FORMATIONS PENETRATED BY A BOREHOLD, COMPRISING: POSITIONING A SIDE POCKET MANDREL ADJACENT EACH OF SAID EARTH FORMATIONS INTERCONNECTED AND SUSPENDED FROM THE EARTH''S SURFACE BY PIPE STRING SECTIONS TO FORM A SINGLE PIPE STRING HAVING A CONTINUOUS BORE EXTENDING FROM THE EARTH''S SURFACE TO SUBSTANTIALLY THE BOTTOM OF THE BOREHOLE; CEMENTING THE PIPE STRING TO THE WALLS OF THE BOREHOLE FROM THE BOREHOLE BOTTOM TO A LEVEL ABOVE THE UPPERMOST OF SAID HYDROCARBON-PRODUCTIVE EARTH FORMATIONS; SUCCESSIVELY POSITIONING A PERFORATING GUN IN THE SIDE POCKETS OF SAID MANDRELS AND PERFORATING SAID MANDRELS THROUGH THE SIDE POCKETS; BLANKING OFF ALL BUT ONE OF SAID PERFORATED SIDE POCKETS; AND INSERTING CHECK VALVE MEANS IN AT LEAST ONE SIDE POCKET, AND INJECTING FLUIDS THROUGH SAID CHECK VALVE MEANS AND THE PERFORATIONS IN SAID AT LEAST ONE SIDE POCKET. 